AuthorTopic: Noonan Navigation Error (Read 157510 times)

It is hardly to believe that a pilot goes to a lavatory in the back of his plane by crawling over tanks , leaving all controls alone , even with automatic pilot instruments or an (unlicensed) stand in . Pilots do not even think about that . There are good questions having no answer ...

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I hate to let this little secret out of the bag but the fact is that flying a plane during cruise is very, very easy to do. It is the first thing introduced to a student pilot and he flies the plane in cruise on the very first lesson and gets good at it by the end of hour four. I had my daughter doing it when she was four years old and she couldn't see over the top of the instrument panel so she had to fly on instruments! So Noonan, even if he didn't fly often (he did have a pilot certificate), certainly had the ability to fly the plane while Earhart went to the back to use the potty.

You wouldn't want to just trust the autopilot when you leave the cockpit.

The 230 pound pilot was flying alone by himself in his plane with the autopilot engaged. He had removed all of the seats (except the pilot seat) so he could carry some bulky objects but the cabin was empty at the time of the accident. He had also purchased a portable "potty" from a camping equipment store and had placed it in the baggage area of the cabin, all the way in back. He was flying along at 21,000 feet on autopilot when he decided to use the "potty." He got up from his seat and walked to the back of the cabin and sat down on the "potty." He apparently had not calculated how much the center of gravity would shift in the lightly loaded plane when his weight was moved back about a hundred and twenty inches. I did the calculation after the accident and determined that the center of gravity moved about three inches out of the back of the allowable center of gravity envelope. The autpilot tripped off and the nose pitched up and the plane spun in from 21,000 feet. We know that this is what happened because the autopilot had trimmed the nose full down to try to deal with the heavy weight of the pilot all the way back in the cabin but this was not enough to maintain control. We also know that this is what happened because, after the ground fire, the only parts of the pilot's body that were not burned was his back which was against the pressure bulkhead at the back of the cabin and his butt cheeks sitting on the "potty." (The calculation of the shift of the COG is easy since it moves in the ratio of the weight being shifted to the gross weight of the plane times the distance the weight is moved. If you move a weight that is one-tenth the weight of the plane twenty inches then the COG will shift two inches, one-tenth the distance that the weight was moved.)

( I call these "stupid pilot tricks")

He may have gotten away with this on prior flights but this time the plane was lightly loaded so his weight shift had a greater effect on the center of gravity than if the plane had been heavily loaded. And with the seats removed he had nothing to grab onto to pull himself up forward to regain the pilot seat.

If the navigator has precomputed a list of (running) time-coordinates groups (like Noonan evidently did for sunset) , an uncertainty sunset line band may get very narrow as can be seen from the position report @ 27 mls west of Nukumanu . The precomputation is somewhat extensive , but not intricate , and (ex) sea navigators being more familiar with calculation than air navigators who only learned to read tables , had no problem with it . The accuracy of the method initially suffered negative criticism since many navigators only reckoned for refraction/parallax/semi-diam. (-53´) , neglecting horizon dip (since early ships had the decks & bridge close to sea level , but later ships were higher) . With dip (separately) inserted in the algorithm , the reduction gains much more accuracy . Citing Cugle - 1943 , p. 550 of 14th imprint (first 1924) : "As it is very doubtful that a proper contact with sun and horizon has been noted , this observation is not to be entirely relied upon , but the navigator should understand it as it is often the case that he does not get any sights during the day , and the sun sets in the clear . He can then get a fairly good idea of his longitude of this problem" . (follow the rules for computation , using Tab. 33 & 34 of H.O.no.9-II , American Practical Navigator) .

If the navigator has precomputed a list of (running) time-coordinates groups (like Noonan evidently did for sunset) , an uncertainty sunset line band may get very narrow as can be seen from the position report @ 27 mls west of Nukumanu . The precomputation is somewhat extensive , but not intricate , and (ex) sea navigators being more familiar with calculation than air navigators who only learned to read tables , had no problem with it . The accuracy of the method initially suffered negative criticism since many navigators only reckoned for refraction/parallax/semi-diam. (-53´) , neglecting horizon dip (since early ships had the decks & bridge close to sea level , but later ships were higher) . With dip (separately) inserted in the algorithm , the reduction gains much more accuracy . Citing Cugle - 1943 , p. 550 of 14th imprint (first 1924) : "As it is very doubtful that a proper contact with sun and horizon has been noted , this observation is not to be entirely relied upon , but the navigator should understand it as it is often the case that he does not get any sights during the day , and the sun sets in the clear . He can then get a fairly good idea of his longitude of this problem" . (follow the rules for computation , using Tab. 33 & 34 of H.O.no.9-II , American Practical Navigator) .

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The sun doesn't set or rise in the clear very often so nobody would plan on using it for finding an island before the fuel ran out in an airplane. From this quote it is clearly an emergency method only used if sights could not be obtained in the normal manner. And "fairly good" isn't good enough to find Howland. And Cugle wasn't using the sunrise table from the Nautical Almanac as you claim Noonan would do but was doing the normal celestial navigation trig. And Cugle was talking about using it on a ship, not in an airplane where the much greater values for the "dip" correction (which varies with the height of the observer's eye above the sea), and the size of this correction cannot be accurately determined in flight (as I told you before Mr. van Asten) due to inaccuracies in the altimeter. On a ship you can measure your height of eye above sea level to the nearest inch if you want so there is no uncertainty in the proper dip correction value to apply.

And we have thoroughly debunked your "sunset" observation derived fix before, the coordinates of which were received by radio in Lae one and a half minutes before the time that you claim the observation was taken!

Mr.Lapook , I have recently sent to you texts from Cugle "Practical Navigation" . This manual uses the tables of H.O.no.9-II . The sunset - sunrise method for longitude appears in the imprints 1924 through 1943 . Also in "Precision Astrolabe" by Rogers it is recorded that Portuguese navigators of early transatlantic crossing established longitude at sunrise . It is true that it is an "emergency" fashion , but if no body other than the sun is available , it is the best you have . Mr. Noonan plotted an advanced sunline over Howland in his chart , can anybody answer to the good question how he would have done that without a sunrise observation which also gave him the distance to Howland , 100 mls out @ GMT 1815 ?

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This emergency method is intended for someone without a sextant and so without the ability to measure the height of the sun accurately. In such a case a bare eyeball observation of sunrise might be "the best thing you have", anything is better than nothing. But it was not the "best thing that Noonan had" since he had a sextant and could take shots of the sun at altitudes that allowed for much more accurate position fixes than the range of 40 NM of errors (minimum if used on a ship and much more if tried in flight) using the van Asten sunrise theory. And then van Asten has Noonan dead reckoning for an additional 130 miles adding an additional 13 miles to the band of errors so that Noonan would have had a minimum error band of 53 miles and more likely approaching 100 NM if tried in flight. There was little chance that the van Asten method would get the plane anywhere close enough to see the island. Noonan would have used the standard landfall procedure of taking sextant shots as they neared the LOP and additional ones while tracking the LOP.

For those who don't follow the navigational arcana here is a simple way to see why Noonan would never have planned to use a sunrise observation. I think we have all been on a beach watching the sun go down. Think back to your own observations. Were you able to actually see the upper limb of the sun disappear behind the sea horizon? Hmmm? Probably not unless you have looked for it many times. The vast majority of the time there are clouds between you and the horizon and even more clouds beyond the horizon and the sun sinks behind the clouds, not behind the sea horizon. The clouds prevent you from accurately determining the time the sun is actually aligned with the true horizon and every four seconds of error in this timing causes a one nautical mile error in the derived position line. It is an even bigger problem if trying to do this in flight because the horizon is much farther away so providing a much greater opportunity for clouds to block the view. In 2009 I sailed across the Atlantic on the Royal Clipper, see

We were 10 days at sea so there were ten sunrises and ten sunsets and I was up every morning before sunrise to shoot the stars and everybody was on deck to catch the sunsets. So, how many sunsets and sunrises was I able to time as the sun set or rose from the sea horizon? just three times out of a possible 20! Clouds blocked the observations 17 out of 20 times. And that was from sea level, on a ship, not in an airplane.

You can repeat this experiment for yourself, just hang out at the beach.

I'm not going to be dragged back into refuting Mr. van Asten's theories one by one which I have responded to before. He keeps bringing them up as if they had not already been refuted. I will use this one example to show the pattern. He now claims that Rogers wrote that the Portuguese navigators (Gago Coutinho) used his method of using sunrise for determining longitude. I wrote before:

"Coutinho in 1922 took 40 observations with a mariner's sextant but the lowest altitude he measured was 16° 15', nowhere near the "van Asten horizon." (And nowhere near sunrise.)

But van Asten just brings it up again and again, this is his pattern.

Just go back and read the replies starting in May 2011 and you will see that Mr. van Asten's theories don't make any sense.

All : yes , but I still have no reply to my questions (now two) : 1 . How did Noonan advance a sunline over Howland , without having observed sunrise and established his distance off , 150 mls @ 1755 , 100 mls @ 1815 GMT ?. 2 . How did Noonan establish the GMT 0720 ( not 0718 , see earlier comments) reported position , other than by sunset , btw with a bubble sextant @ high altitude , the horizon visibility of no importance since the entire sun is above it due refraction , dip not applicable for the type of sextant ?

By P&DR and CEL/ NAV they got to where RDF could have, should have allowed them to find their way to Howland.Read the Chater Report (Tighar Archived Documents) and you will see that AE used her RDF in a test flight at Lae and was unable to find a null (get a bearing) on the Lae station. After landing, she “assumed” that the reason was that they were too close to the station. It is hard to understand how a pilot, knowing that the RDF would lead them directly to Howland once they got to about 200 miles of the island, would take off on a 2500 mile trip completely over water without knowing absolutely that the RDF was working properly.

AE also , apparently, had no understanding of the limitations on the RDFs on the Itasca and onshore at Howland. She kept asking them to take bearings on her using frequencies that their equipment couldn’t operate in. She knew, or should have known, this before takeoff. She didn’t and we all know the result, they (AE and FN) didn’t find Howland.

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To those who don't do celestial navigation I know it appears to be a black art, witchcraft, voodoo and so everybody seems to discount its accuracy. Celestial navigation is accurate enough, all by itself, to allow Noonan to find Howland. I have read ad nauseum that celnav was only supposed to get them close enough to get within radio range and that they NEEDED radio to actually find the island. I am attaching a couple of pages from Air Force manuals showing that celnav is all that is needed to find small islands, no need for radio in addition. In previous replies I have shown that thousands of single engine planes, flown by solo pilots, used just dead reckoning to cross the Pacific knowing that dead reckoning was accurate enough to get them within radio range so that they could find the airports with their RDF. These legs across the Pacific were longer than the Lae to Howland leg. So if Earhart was planning to rely solely on RDF to find the island then she didn't need Fred. As further proof that they planned to have their celnav accurate enough to find the island is their wasting several days to get a check of the chronometers. Accurate time is only needed to find longitude, not latitude. Since they were flying basically east they only had to make sure that their latitude was accurate enough to make sure that they did not pass too far to the north or south so as to not come within the radio range of Itasca's transmitter which is more than 200 NM. If Noonan's chrometers had been error a whole WEEK their calculated latitude would have been off by only 40'. the same as 40 NM.

But the reason that she hauled Fred all the way around the world was to have a separate, independent redundant method for finding Howland. They had had other problems with their radios on the flight so they knew that they needed a second method for completing the flight.

I agree with you, I would have wanted to know that my RDF was working and I would have made checks while flying away from Lae. I always tracked outbound with my ADF tuned to the station at the departure island and if I couldn't get my ADF to work then I would have turned back to get the radio fixed. They didn't do this so they were satisfied that celnav would be good enough to get them to Howland and they gave up the demand for two redundant systems.

All : yes , but I still have no reply to my questions (now two) : 1 . How did Noonan advance a sunline over Howland , without having observed sunrise and established his distance off , 150 mls @ 1755 , 100 mls @ 1815 GMT ?. 2 . How did Noonan establish the GMT 0720 ( not 0718 , see earlier comments) reported position , other than by sunset , btw with a bubble sextant @ high altitude , the horizon visibility of no importance since the entire sun is above it due refraction , dip not applicable for the type of sextant ?

--------------------1. He measured the altitude of the sun with his bubble sextant when it was above six degrees, and he did this several times.

2. He established the position and reported it and the report was received at 0718 Z according to the Chatter Report (one and a half minutes prior to the time of the observation according to your theory) by looking out the window and seeing the west end of Nukumanu Islands. You should rely on primary sources like the Chatter Report instead of some secondary source that erroneously rounded the reporting time to 0720 Z. This slight discrepancy has absolutely no relevance in all other discussions involving the navigation on this flight so there was no reason to correct it in the literature. It only has relevance to your theory as you are the only one claiming that he observed sunset to get a fix and that that observation must have taken place at 0719:30 Z, a minute and a half after the position report was received in Lae.

3. As to the use of the bubble sextant, you have now changed your story since your whole theory in your prior posts and in your 2008 article was that he mistakenly used the marine sextant for the sunrise observation.

MartyMy first flight in a commercial passenger airplane was in a Trans-Texas Airways Douglas DC-3, a twin engined , low-winged monoplane, tail-dragger that could carry 20 to 25 passengers. Its nickname was gained because of its behaviour in turbulence "The Vomit Comet". Oh My, the things we store away in our memory banks.

The HERE (Human Element Range Extender, a quart Jar, worked well last winter when my wife and I were stranded on I-80 in the Sierras for 9 hours because an 18 wheeler jackknifed and blocked both west-bound lanes.

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You can always pee on the side of the road, and I have seen women do it too, but it is hard to accomplish the same on the side of a cloud.

1. Impossible , @ 1815 GMT sun´s elevation was far below 6 deg , nevertheless distance off was recorded . 2. About 0720 navigator had the sun only for observation , seeing the west shores of Nukumanu from 27 mls , 43 km is doubtful , separately from the specific coordinates communicated , these are by exactness for sunset , not discovered by van Asten , but by mathematics . 3 . No story changed , @ sunset the bubble sextant was used , see EJN-2011. H.

Not Coutinho but air navigator A.W.Brown (pilot J.Alcock) , June 1919 , ckecked position at sunrise : " At sunrise Brown was prepared to check his position by observing the azimuth of the sun ... At five in the morning he obtained a sun line with his artificial horizon and as of 0720 worked out a fix " (evidently via sin Z = sin d / cos L , H) . (Rogers , p.70 , A/c was @ 400 ft altitude) . Navigator G.G.H.Cooke of airship R 34 , btw used a marine sextant on the sea horizon for sights on the sun .

1. Impossible , @ 1815 GMT sun´s elevation was far below 6 deg , nevertheless distance off was recorded . 2. About 0720 navigator had the sun only for observation , seeing the west shores of Nukumanu from 27 mls , 43 km is doubtful , separately from the specific coordinates communicated , these are by exactness for sunset , not discovered by van Asten , but by mathematics . 3 . No story changed , @ sunset the bubble sextant was used , see EJN-2011. H.

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Mr. van Asten,

Thanks for giving me the opportunity to point out yet another one of your errors.

Earhart sent a position report at 0718 Z of 4° 33' south, 159° 07' east which is near the tabulated coordinates of Nukumanu island which are 4° 35' south, 159° 30' east. There has been discussion as to whether Earhart had a visual fix on the island and that she was reporting the coordinates of the island given to her by Noonan as shown on his chart with the assumption that there was an error in the actual coordinates in 1937 because the position report was 23 NM west of the published location. In fact, the published coordinates have been known since at least 1890 when they were published in the British Government publication, Pacific Islands Sailing Directions, so this doesn't explain the discrepancy as it is obvious that the island would have been correctly depicted on Noonan's chart. What does explain the discrepancy is that the published location is for the easternmost point of the atoll which is actually 11 NM long east to west so the westernmost point is at 159° 19' east, only 12 NM from the position given by Noonan. Given the scale of the chart used by Noonan this is a very small distance. Another possibility is that Noonan simply estimated that they were several nautical miles from the western end on the island and gave those estimated coordinates. You apparently thought that Nukumanu was just a geometrical point, infinitely small, (this is in keeping with all of your other posts where you work with mathematics to about ten decimal places instead of the reality of the much lower level of navigational precision in the real world) and you just read off its published location instead of realizing that Nukumanu is a real island with actual dimensions, not some theoretical mathematical construct.

1. Impossible , @ 1815 GMT sun´s elevation was far below 6 deg , nevertheless distance off was recorded . 2. About 0720 navigator had the sun only for observation , seeing the west shores of Nukumanu from 27 mls , 43 km is doubtful , separately from the specific coordinates communicated , these are by exactness for sunset , not discovered by van Asten , but by mathematics . 3 . No story changed , @ sunset the bubble sextant was used , see EJN-2011. H.

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This is so funny, so now it's "about" 0720! LOL!

Van Asten still has not explained how Earhart's radio waves managed to travel faster than the speed of light and go back in time so as to be received at Lae at 0718, a minute and a half before the 0719:30 time that van Asten claims that Noonan observed sunset. The time of this observation is critical to van Asten's theory since his whole theory is based on his mathematical (ten decimal places again) computation of this time. If Noonan had actually made an observation at 0719:30 then the position could not have been transmitted at 0720. Taking an observation with a bubble sextant in flight, as van Asten says Noonan was doing for this observation, takes about three minutes as you must take at least ten observations and average them to arrive at an accurate observation. The average time of all of these individual observations is the time used for the observation, again this is something van Asten doesn't understand. If Noonan actually did compute his position based on a sun observation that had an average time of 0719:30 then he was shooting the sun for about three minutes from about 0718:15 to about 0720:45. Then he had to figure out the average of the ten (or more, taking even more time) by hand which takes about an additional minute and a half (try it yourself using degrees and minutes of arc as read off a sextant) and about another minute to refer to his precalculated altitude data, so the claimed 0719:30 observation would not have been completed until about 0723:15 which is more than three minutes later than van Asten claims that the position report was transmitted. It is also more than five minutes after the report was actually received in Lae!

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